Particulate matter in indoor spaces: known facts and the knowledge gaps*

Abstract: Particulate matter in indoor spaces: known facts and the knowledge gaps. As people spend most of the time in closed spaces (flats, workplaces, schools etc.), the indoor air has been researched for many years all over the world. Particulate matter (PM) is one of the most often examined pollutants in the indoor and outdoor air. The following study presents the facts about PM in closed spaces and the most often taken actions. The least known aspects related to the indoor air pollution with PM are demonstrated. The indoor space of various service and office buildings/facilities (not related to production, i.e. offices, shops, beauty parlours, restaurant kitchens, restaurants, pubs etc.) seem to be an unrecognized area in the air pollution studies. Importantly, a great number of people work in such spaces all over the world and thus spend there a large part of their lives.